U.S. Pat. No. 5,466,113 describes an arrangement for securing an implement to a lifting arm, that includes a locking bar that can be moved manually between a locking position, in which it retains the implement at the lifting arm, and an unlocking position, in which it releases the implement. In the unlocking position, the locking bar can be arrested by pivoting it in a first direction between initial and arresting positions about a locking axis. After the attachment of an implement, it is brought into the locking position automatically by pivoting the implement under hydraulic power towards the lifting boom until the locking bar is engaged by the lifting boom and pivoted back to its initial position. However, due to the manual operation of the locking bar, the operator must move to the implement in order to unlock the locking bar. In this publication, a motorized movement of the locking bar into the unlocking position is also proposed. However, it is not disclosed how the locking bar is retained or arrested in the unlocking position in such a configuration, nor how it is to be brought back into the locking position.
Another known lifting arm arrangement is disclosed in FR 2 776 316 A. In this patent, a locking bar is moved by a hydraulic motor in order to secure an implement. To unlock the implement, a key or switch push button is actuated on a handgrip in the region of the operator's station, so that the hydraulic motor is supplied with fluid and brings the locking bar into the unlocking position. Indeed, in order to lock an implement, a further actuation of a key is necessary in order to end the supply of fluid to the hydraulic motor and to bring the locking bar into the locking position. Hence, this solution is also not operator friendly.
The problem underlying the invention is seen in the need to provide an ergonomically favorable arrangement for securing an implement on a lifting arm in which the aforementioned disadvantages have been eliminated.